This project, a collaborative effort by the NCI, NAS, EPA and other Federal agencies, was initiated to provide more data relative to skin cancer and harmful solar ultraviolet. An urgent need for these data has existed since recent scientific reports have warned about the decomposition of stratospheric ozone by nitrogen oxides and chlorofluoromethanes (CFM's). Federal regulatory agencies have already recommended bans on the use of aerosol spray cans which use CFM's as propellants. Recent National Academy of Science (NAS) reports suggest a five to 16% ozone depletion during the next century. Critical reviews will be made of all pertinent information dealing with estimates of increased human skin cancer due to excess amounts of UV-B reaching the earth's surface. As mandated by Public Law 95-95 (amendment to the Clear Air Act of l977), the NCI is continuing its investigations in this area. As more surveys are included more reliable estimates of the degree of morbidity from skin cancer will be derived. In addition, new estimates of skin cancer risks adjusted for certain host and environmental factors (including those other than UV exposure) will be ascertained (e.g., ethnicity, skin complexion, exposure to ionizing radiation, coal tar, skin conditions other than cancer, occupation).